1 Technical Field of the Invention
The present invention relates to storage of secret data and, more particularly, to a storage of secret data through use of a mutation cycle of a cell array.
2. Background Art
Most computer applications make no deliberate attempt to secure secrets during execution. Rather, they store secret values so as to be plainly readable in memory at all times, making them vulnerable to any process that can gain access to that memory. For example, an active program can search a hard disk looking for particular subject matter holding a secret. Once found, the secret or program holding the secret may be analyzed and/or destroyed. The secret and program may be removed or copied from the hard disk via a modem for remote analysis.
More sophisticated applications only have secrets plainly readable in memory, or "in the clear," at times when they are actually in use. The remainder of the time, they are kept in some encrypted form. This has the problem that another secret must be employed to decrypt the stored secrets. This protecting secret must then be protected for the values to be secure. Decrypting the various secrets can be time consuming. For example, the encrypted secrets may be stored on hard disks which require time to access.
U.S. patent application Ser. No. 08/662,679, filed Jun. 13, 1996, now U.S. Pat. No. 5,892,899, issued Apr. 6, 1999, entitled "Tamper Resistant Method and Apparatus", now U.S. Pat. No. 5,892,899, of Aucsmith et al. describes a tamper resistant procedure in which cells are exclusive-ORed with other cells to create mutations. The pattern of execution of this procedure may be the protecting secret. However, if bits are altered, the cells do not properly mutate.
Accordingly, there is a need for a method and apparatus to securely store secret data in such a way that the secret data may be rapidly stored and retrieved.